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So after using the DSC last season with unreal results I decided to go all in and install the Tractive shocks. I am very fortunate to be local to TPC and have worked with them for years. The DSC made such a big difference alone I was truly amazed! Last season Mike from TPC was at a couple of events that I was also attending and was nice enough to take the time to custom tune my DSC which I already was very happy with. Honestly I didn't expect to notice a difference being the car was working very well already, but wow I was wrong. I picked up .7 of a second from my best lap ever on my home track. Because of how impressed I am with the DSC I decided to take the next step and add the Tractive shocks. I also had them rebuild my LSD which was completely toast! TPC (Tom) made sure the car was perfectly setup. I can't wait to get on the track and give my new setup a good test. I will report back after my first track day which should be in the next week or so.
I want to publicly thank Tom, Mike and all of TPC/DSC for spending the extra time and attention to detail on this project!
Here's a little something to get you excited while you wait to get out on track!
Just had a customer submit this video to us of him pulling a 1:58 at VIR with the DSC/Tractive setup, as well as TPC Racing sway bars, drop links, and toe links!
Are the second smaller springs simply helper springs that are fully compressed under normal load and just exist to maintain load on the main spring at full travel?
It just struck me while doing some suspension research, was there any reason why you guys didn't try to go the dual spring route for the tractive coilovers with the softer spring stacked such that there remains some travel left to absorb bumps and such?
Given the dynamic damping and range of the dampers I'd have thought something like that would be an even better solution than going with a single main spring (60F 110R N/mm iirc) as the damping would be able to adjust to the softer springs better as required as well as the firmer main spring than a passive damper that would be valved mainly to work with the main spring.
Are the second smaller springs simply helper springs that are fully compressed under normal load and just exist to maintain load on the main spring at full travel?
It just struck me while doing some suspension research, was there any reason why you guys didn't try to go the dual spring route for the tractive coilovers with the softer spring stacked such that there remains some travel left to absorb bumps and such?
Given the dynamic damping and range of the dampers I'd have thought something like that would be an even better solution than going with a single main spring (60F 110R N/mm iirc) as the damping would be able to adjust to the softer springs better as required as well as the firmer main spring than a passive damper that would be valved mainly to work with the main spring.
The smaller(gold color) springs are helper springs. These helper springs are rated at 30nm(or 168 lbs). They do fully compress to the weight of the car. When a tire comes off the ground the helper springs do take the initial compression of the landing to soften the impact to some degree before the main springs come in to effect. So it does work as sort of a two-stage during landing.
As for two-stage while at ride height, well, factory progressively-wound springs do that by having unevenly spaced coils and bell-shaped design. The non-symmetrical shape and unevenly spaced coils compress sooner at one end than the other to create two-stage effect. You could use factory bell-shaped springs on Tractives but will require A LOT of time in tuning the mapping and in the end may not produce an appreciable gain. That's why many suspension tuners favor linear-rate springs over progressive(multi-stage). I can't speak for other brands but its likely for this reason the major premier brand motorsport damper companies don't use multi-stage springs at ride height. We have found that a single linear-rate main spring to be more than satisfactory.
Just FYI, this is an older image. On 997 cars we on longer use helper springs for the front. We use a longer main spring instead because we have found the longer front main springs to control the movements better than a shorter springs due to better length of spring wire to force ratio.
The smaller(gold color) springs are helper springs. These helper springs are rated at 30nm(or 168 lbs). They do fully compress to the weight of the car. When a tire comes off the ground the helper springs do take the initial compression of the landing to soften the impact to some degree before the main springs come in to effect. So it does work as sort of a two-stage during landing.
Ok thanks, makes sense.
Originally Posted by Tom-TPC Racing
As for two-stage while at ride height, well, factory progressively-wound springs do that by having unevenly spaced coils and bell-shaped design. The non-symmetrical shape and unevenly spaced coils compress sooner at one end than the other to create two-stage effect. You could use factory bell-shaped springs on Tractives but will require A LOT of time in tuning the mapping and in the end may not produce an appreciable gain. That's why many suspension tuners favor linear-rate springs over progressive(multi-stage). I can't speak for other brands but its likely for this reason the major premier brand motorsport damper companies don't use multi-stage springs at ride height. We have found that a single linear-rate main spring to be more than satisfactory.
Just FYI, this is an older image. On 997 cars we on longer use helper springs for the front. We use a longer main spring instead because we have found the longer front main springs to control the movements better than a shorter springs due to better length of spring wire to force ratio.
I was more thinking of 2 linear springs stacked together with a bit of travel left in the tender spring that quickly blocks up with any serious dynamic forces to the much firmer main spring while giving some kind of reasonable compliance than a progressive spring (like the OEM factory one). AFAIK some of the earlier Cup cars did race with a dual spring setup similar to that especially on bumpy tracks. Interesting you thought a single intermediate main spring was sufficient though.
For explanation, I just recently put a DSC box onto my car (7.2RS) and while i did think it was an improvement on track (especially on fast transitions) I was thinking there would be more of a change on the 'soft' mode on the road as well so was just wondering if there was anything that could get me in terms of having my cake and eating it being better on the road and track and some of the 'tender springs' discussions here on RL were pretty thought provoking.
I was more thinking of 2 linear springs stacked together with a bit of travel left in the tender spring that quickly blocks up with any serious dynamic forces to the much firmer main spring while giving some kind of reasonable compliance than a progressive spring (like the OEM factory one). AFAIK some of the earlier Cup cars did race with a dual spring setup similar to that especially on bumpy tracks. Interesting you thought a single intermediate main spring was sufficient though.
The idea is good but will require A LOT of testing to perfect the seamless transition from compressing one spring to the next. If there's a big enough gap in spring pressure during the transitioning from one spring to the next then the travel stroke will not be smooth and will be counterproductive. Imagine a spring pressure graph with a step, this would reduce tire grip and we'd have to make the shocks do more work to mask the step just to be back in square one, theoretically. We find the front single main spring to do what we want it to do for a majority of street and track cars. We do use front helper springs for applications using a stroke/length/ride height combo that results in loose spring on full droop.
And please don't forget Tractive DDA shocks can produce more damping force at peak load via DSC commands than the spring pressure that we use, so achieving wider movement resistance range while optimizing compliance is already being done by by the Tractive DDA shocks and the DSC controller.
Interesting info on the early Cup car dual rate springs. We started racing Cup cars in year 2000. From 2000 on they all have helper springs but these helper springs fully collapse to the car's weight. It must be the early 1999 Cup cars that has the dual rate which I have not had the honor to see.
Originally Posted by isv
For explanation, I just recently put a DSC box onto my car (7.2RS) and while i did think it was an improvement on track (especially on fast transitions) I was thinking there would be more of a change on the 'soft' mode on the road as well so was just wondering if there was anything that could get me in terms of having my cake and eating it being better on the road and track and some of the 'tender springs' discussions here on RL were pretty thought provoking.
You can use DSC tuning software to lower the Default Rate in the G Comfort Parameters. For exmaple, if the Default Rate value is 10, you can lower it to 5 or 3 or even 1. This value is the % of damping force at zero load. The lower the value the less damping force.
But keep in mind that if the front sway bar is adjusted to stiffer setting the car will be only be as compliant as the sway bar pressure rate allows. And same applies if stiffer springs are installed, which the increased spring pressure will negate lower damper force of the shocks. And also if the ride height is low enough to contact the internal bump rubber then bump rubber will negate the shocks.
You can use DSC tuning software to lower the Default Rate in the G Comfort Parameters. For exmaple, if the Default Rate value is 10, you can lower it to 5 or 3 or even 1. This value is the % of damping force at zero load. The lower the value the less damping force.
But keep in mind that if the front sway bar is adjusted to stiffer setting the car will be only be as compliant as the sway bar pressure rate allows. And same applies if stiffer springs are installed, which the increased spring pressure will negate lower damper force of the shocks. And also if the ride height is low enough to contact the internal bump rubber then bump rubber will negate the shocks.
Thanks, will have a look. Ride comfort as stock was always fine anyway and now with the dsc box the car porpoises less over poor surfaces. I guess I was just expecting a bigger change.
So I drove the car on track and I am very happy with the results! 1st session of the day/year I matched my personal best. Second session I beat it by a full second and third I picked up another couple of tenths. I was able to consistently run laps at or better than my prior best and several laps in my 2nd and 3rd session a second or better faster! The car felt extremely stable in corners, braking and at speed on the fast sections. The set up is very confidence inspiring!
I also want to say that Tom from TPC called me a couple of times to see how things were going and see if I needed any support. So thank you Tom/TPC for the above and beyond customer support!! If anyone is thinking of going this route I think you will be very happy with the product and the customer support!
I also want to say that Tom from TPC called me a couple of times to see how things were going and see if I needed any support. So thank you Tom/TPC for the above and beyond customer support!! If anyone is thinking of going this route I think you will be very happy with the product and the customer support!
Sorry I added this to my prior post thinking I could delete this one, but I guess I can't.
Last edited by MX RACER; 04-17-2017 at 05:55 PM.
Reason: correction
04-05-2017, 03:08 PM
Tractive + DSC installed
